We already know that lean is about reducing waste, by how? Think about the Japanese words Kaizen:

  • Kai = To change
  • Zen = For the better

Kaizen stands for improving things continuously, a peace at times. This continuous improvement is the base of Lean that tries to reduce or remove the seven-element of waste.

The seven-element of waste are:

  • Correction: Defect causes rework, and this is non-valued activity. To solve the error, we need to inspect another non-valued action. Introducing standardized work reduces the defect drastically. Poka-Yoke is another way to minimize rework by designing the process in a way that becomes impossible to make an error. This kind of waste becomes more impacting in batch production.
Example: In Scrum, attaching acceptance criteria to the item in a backlog, that is, a sort of to-do list, is a way to avoid defects by standardization.
  • Overprocessing: Rework is a form of overprocessing. Also, give a customer features that he doesn’t need or expect. You can solve this by asking the customer for the part he needs.
Example: In Scrum, we have the Product Owner who puts requirements in the form of an item in the Product Backlog. Next, he orders it by value. Starting with the most valued items is a way to avoid doing things you don't need.
  • Conveyance: Unnecessary movement of output, product, or resources. To solve this problem, you need to fix the position of things.
Example: In IT, an example of unnecessary movement is when you use more than one software, and you need to copy information from one to another to end one task. In this case, the solution is integrating the software to avoid this kind of waste.
  • Motion: The waste of motion is about the unnecessary movement of people. It’s different from conveyance because you move people instead of a thing. To solve this problem, you need to fix the position of people.
Example: In IT, an example of unnecessary movement of people can be about task switching, so when people work on more than one task and lose time switching from one task to another. For example, Kanban try to make a limit to this problem, limiting the work in progress (WIP) 
  • Waiting: is about material waiting for processing, the client waiting to be served, or maybe the entire process waiting for something. We can use the Single Minute Exchange of Dies (SMED) to solve this problem. It is a collection of techniques that works by separating the external setup time (that is what I can do for the next step while the actual step is still working) and the internal setup time (that are things that I can’t do until the actual step is still working). In the end, SMED tries to anticipate the external setup time works.
Example: In IT, we can have an instance of waiting everywhere, for example, people waiting for the technical analysis's end before starting work. Scrum, for example, avoids this waiting, removing upfront analysis and promoting a Just In Time way of working.
  • Inventory: is about the undone product that needs work to be finished. Inventory locks capital and is subject to deprecation. You need to avoid using an extensive inventory, trying to get the necessary material Just In Time.
Example: In the IT field, inventory can be unfinished functionality that you can't already sell. Kanban or Scrum try to limit the work in progress to fast marketable functions.
  • Overproduction: This is about making more products than demand, which leads to write-offs. Pull production or CRM help to look at your output and avoid overproduction.
Example: In the IT field, overproduction is more about making more than what the client asks, also called gold platting. Scrum tries to avoid this by the product backlog artifact and the role of the product owner. They are the voice of the customer who assesses what's needed.

We also have the eighth form of waste, which is the waste of skills you have by unutilized talents. Again, the way to reduce this waste is to give visibility to people’s skills in the company and what they do.

For the exam you need to remember:

  • The Seven forms of waste are Correction, Overprocessing, Conveyance, Motion, Waiting, Inventory, and Overproduction;
  • Remember that Conveyance is about output or raw material. Instead, Motion is about people;
  • You also have the eighth form of waste, waste of skills.


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